r600/sfn: Always start a new CF after a KILL instruction

Docu says:

   Ensure that the KILL* instruction is the last instruction
   in an ALU clause, because the remaining instructions executed
   in the clause do not reflect the updated valid state after
   the kill operation.

Fixes: 79ca456b48
    r600/sfn: rewrite NIR backend

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18983>
(cherry picked from commit 99b7a12ec1)

.pick_status.json

@@ -1021,7 +1021,7 @@
         "description": "r600/sfn: Always start a new CF after a KILL instruction",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": "79ca456b4837b3bc21cf9ef3c03c505c4b4909f6"
     },

src/gallium/drivers/r600/sfn/sfn_instr_alugroup.cpp

@@ -35,6 +35,25 @@ AluGroup::AluGroup()
    std::fill(m_slots.begin(), m_slots.end(), nullptr);
 }
 
+static bool is_kill(EAluOp op)
+{
+   switch (op) {
+   case op2_kille:
+   case op2_kille_int:
+   case op2_killne:
+   case op2_killne_int:
+   case op2_killge:
+   case op2_killge_int:
+   case op2_killge_uint:
+   case op2_killgt:
+   case op2_killgt_int:
+   case op2_killgt_uint:
+      return true;
+   default:
+      return false;
+   }
+}
+
 bool AluGroup::add_instruction(AluInstr *instr)
 {
    /* we can only schedule one op that accesses LDS or
@@ -45,12 +64,17 @@ bool AluGroup::add_instruction(AluInstr *instr)
    if (instr->has_alu_flag(alu_is_trans)) {
       auto opinfo = alu_ops.find(instr->opcode());
       assert(opinfo->second.can_channel(AluOp::t, s_chip_class));
-      if (add_trans_instructions(instr))
+      if (add_trans_instructions(instr)) {
+         if (is_kill(instr->opcode()))
+            m_has_kill_op = true;
          return true;
+      }
    }
 
    if (add_vec_instructions(instr) && !instr->has_alu_flag(alu_is_trans)) {
       instr->set_parent_group(this);
+      if (!instr->has_alu_flag(alu_is_lds) && is_kill(instr->opcode()))
+         m_has_kill_op = true;
       return true;
    }
 
@@ -61,6 +85,8 @@ bool AluGroup::add_instruction(AluInstr *instr)
        opinfo->second.can_channel(AluOp::t, s_chip_class) &&
        add_trans_instructions(instr)) {
       instr->set_parent_group(this);
+      if (is_kill(instr->opcode()))
+         m_has_kill_op = true;
       return true;
    }
 

src/gallium/drivers/r600/sfn/sfn_instr_alugroup.h

@@ -87,6 +87,7 @@ public:
    static bool has_t() { return s_max_slots == 5;}
 
    bool addr_for_src() const { return m_addr_for_src;}
+   bool has_kill_op() const {return m_has_kill_op;}
 
 private:
    void forward_set_blockid(int id, int index) override;
@@ -111,6 +112,7 @@ private:
    bool m_has_lds_op{false};
    bool m_addr_is_index{false};
    bool m_addr_for_src{false};
+   bool m_has_kill_op{false};
 };
 
 

src/gallium/drivers/r600/sfn/sfn_scheduler.cpp

@@ -294,7 +294,6 @@ void BlockSheduler::schedule_block(Block& in_block, Shader::ShaderBlocks& out_bl
    bool have_instr = collect_ready(cir);
 
    m_current_block = new Block(in_block.nesting_depth(), in_block.id());
-
    assert(m_current_block->id() >= 0);
 
    while (have_instr) {
@@ -569,6 +568,13 @@ bool BlockSheduler::schedule_alu(Shader::ShaderBlocks& out_blocks)
    if (group->has_lds_group_end())
       m_current_block->lds_group_end();
 
+   if (group->has_kill_op()) {
+      assert(!group->has_lds_group_start());
+      start_new_block(out_blocks, Block::alu);
+      m_current_block->set_instr_flag(Instr::force_cf);
+   }
+
+
    return success;
 }
 

src/gallium/drivers/r600/sfn/sfn_shader_fs.cpp

@@ -178,6 +178,7 @@ bool FragmentShader::process_stage_intrinsic(nir_intrinsic_instr *intr)
                                     value_factory().zero(),
                                     value_factory().zero(),
                                     {AluInstr::last}));
+      start_new_block(0);
       return true;
    case nir_intrinsic_load_sample_mask_in:
       if (m_apply_sample_mask) {